Portable devices routinely depend upon batteries as a power source. To ease battery replacement costs, rechargeable batteries have found wide utility in powering contemporary consumer and business products. For example, nickel cadmium batteries may be repeatedly used to energize computers, radios, pagers, and other such devices. As is well known, rechargeable batteries may be readily re-energized after use (i.e., after discharge) via a battery charger.
It is often necessary for the charger to retrieve charge information about the battery before or during the charge process. The charger uses the retrieved information to properly charge the battery in accordance with a predetermined charging algorithm. The charger's charging algorithm often requires certain battery parameters, such as battery voltage differential (.DELTA.V) or battery temperature differential (.DELTA.T) which are obtained during the charging process. The (.DELTA.T) is determined by monitoring the battery temperature. The battery temperature is also monitored to prevent explosion of an overheated battery.
Some chargers require additional battery related information, such as information relating to battery capacity. Battery capacity informs the charger as to how much current should be supplied to the battery. For example, based on battery capacity, the charger would provide a substantially higher charge rate to a 1600 mA/Hour than to a 900 mA/Hour battery.
Modem batteries incorporate memory devices which store a wide array of battery-related information, such as the battery capacity, .DELTA.V, .DELTA.t, manufacturing site code, and etc. The charger usually communicates with the memory by a serial data signal which couples to a battery port. Also, serial communication with the memory often requires a synchronization clock signal which is generally provided by the charger to the battery through another battery port.
Batteries interact with external devices via battery ports located on the battery's housing. These battery ports include charger ports for receiving charge current from the charger, supply ports for supplying the battery power to an external device, and battery information port for exchanging charge related information, such as temperature signal, serial data signal, and clock signal. As such, a conventional battery in addition to the battery supply ports may include a battery charger port, a battery temperature port as well as a plurality of battery information ports, i.e., serial data port and clock signal port. However, it is desired to decrease the number of battery ports necessary for charging the battery. Decreasing the number of battery ports reduces the cost and minimizes the risk of battery terminal corrosion when the battery is used under severe conditions.